Nationality: United StatesExecutive summary: One gene, one enzyme theory

American geneticist Edward Tatum helped create the field of molecular genetics with his landmark early work, demonstrating that specific genes control the structure of particular enzymes, by regulating specific chemical processes. "The underlying hypothesis", he wrote, "which in a number of cases has been supported by direct experimental evidence, is that each gene controls the production, function, and specificity of a particular enzyme". For corroborating this "one gene one protein" hypothesis with George Beadle, they were awarded the 1958 Nobel Prize, sharing the honor with Joshua Lederberg.

He was also an accomplished performer on the french horn. A lifelong cigarette smoker, Tatum was killed by emphysema. His father, pharmacologist Arthur Tatum, introduced picrotoxin as an antidote for barbiturate poisoning, and arsenoxide as the first effective pre-penicillin treatment for syphilis.